Scintigraphic study of gastrointestinal transit and disintegration sites of mesalazine tablets labeled with...

Tablets of mesalazine covered with a pH-dependent coating (Pentacol), labeled by an original technique with technetium-99m, were administered to 12 patients, 9 with Crohn's disease, 3 of which recurrent, 1 with ulcerative colitis, and 2 with irritable bowel syndrome, with the aim of verifying in vivo the intestinal site of disintegration and how the contents spread throughout the intestine. In all cases the tablet was broken down in the distal ileum at extremely variable intervals, from 5 to 27 h, and the contents spread into the nearby loops and into the colon. The notable differences in the residence time of the whole tablet in the ileum can be explained by differences in adhesion to the inflamed mucosa and by a lower pH in the part of the ileum affected by the disease.